For years, America’s intelligence community and armed services have recognized climate change as a threat to U.S. national security – shaping a world that is more unstable, resource-constrained, violent, and disaster-prone. This issue is critically important to the world’s most experienced security planners. The impacts are real, and the costs of inaction are unacceptable. America’s elected leaders and private sector must think past tomorrow to focus on this growing problem, and take action at home and abroad.